This work is devoted to analyzing the electrical properties of muscle fibers which are important in the process by which an electrial signal on the surface of a fiber tells the contractile apparatus deep within the muscle to contract. We are particularly interested in measuring the properties of the tubular system of muscle fiber and analyzing its function. The method used is to analyze the equivalent circuit of muscle fibers-- the pathways for current flow--since one component of that circuit is the tubular system. We apply sinusoidal currents and record potential with microelectrodes iserted in the muscle fibers.